<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>新增特性</title>
    <style>
        div {
            /*background-color: red;*/
            width: 200px;
            height: 100px;
            margin: 20px;

            /*设置盒子阴影*/
            box-shadow: 10px 5px 10px red;

            /*设置圆角*/
            border-radius: 10px;

            padding: 10px;
        }

        .class1 {
            background-color: rgba(255, 0, 0, 1);
        }
        .class2 {
            background-color: rgba(255, 0, 0, 0.8);
        }
        .class3 {
            background-color: rgba(255, 0, 0, 0.6);
        }
        .class4 {
            background-color: rgba(255, 0, 0, 0.4);
        }
        .class5 {
            background-color: rgba(255, 0, 0, 0.2);
        }
        .class6 {
            background-color: rgba(255, 0, 0, 0);
        }
        p {
            font-size: 50px;
            /*设置文字阴影*/
            text-shadow: 5px 5px 5px grey;
        }
    </style>
</head>
<body>
    <div class="class1">1</div>
    <div class="class2">1</div>
    <div class="class3">1</div>
    <div class="class4">1</div>
    <div class="class5">1</div>
    <div class="class6">1</div>

    <p>我是p标签</p>
</body>
</html>